It is known that in order to comply with limit values with respect to exhaust components, a regeneration of a nitrogen oxide storage catalytic converter is necessary. Frequently, a rich combustion operation condition is used within the internal combustion engine for this, wherein, by means of the further conveyance of unburned hydrocarbons as far as the storage catalytic converter, its regeneration enabled. Another possibility of providing for a regeneration of a nitrogen oxide storage catalytic converter consists of the use of an injector, which is disposed externally to an exhaust system, for the supplying of reduction agents. There is also the possibility of using a reformer for supplying a reduction agent for the regeneration of the nitrogen oxide storage catalytic converter.